Microgrids

In IEEE standard 2030.7 a microgrid is defined as follows: ‘A group of interconnected loads and distributed energy resources with clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid and can connect and disconnect from the grid to enable it to operate in both grid-connected or island modes’.

[Source: IEEE. IEEE Standard for the Specification of Microgrid Controllers; IEEE Std 2030.7-2017; IEEE: New York, NY, USA, 2018; pp. 1–43.  - Cited in: Sirviö, K., Kauhaniemi, K., Ali Memon, A., Laaksonen, H., Kumpulainen, L., 2020. Functional Analysis of the Microgrid Concept Applied to Case Studies of the Sundom Smart Grid. Energies 13, 4223. https://doi.org/10.3390/en13164223 ]

In IEC-TS 62898-1, a microgrid is defined as follows: ‘Group of interconnected loads and distributed energy resources with defined electrical boundaries that acts as a single controllable entity and is able to operate in both grid-connected and island mode.’ The definition covers both utility microgrids and customer microgrids.

[Source: IEC. Microgrids—Part 1: Guidelines for Microgrid Projects Planning and Specification; IEC/TS 62898-1; IEC: Geneva, Switzerland, 2017; pp. 1–33.  - Cited in: Sirviö, K., Kauhaniemi, K., Ali Memon, A., Laaksonen, H., Kumpulainen, L., 2020. Functional Analysis of the Microgrid Concept Applied to Case Studies of the Sundom Smart Grid. Energies 13, 4223. https://doi.org/10.3390/en13164223 ]

“Level 1 or single customer microgrid. This is a single DER system such as a photovoltaic solar (PV) system, combined heat and power (CHP) or fuel cell (FC) system that is serving one customer through a single meter. This microgrid class is connected to and can island from the distribution grid.

Level 2 or single customer / campus setting; also referred to as the partial feeder microgrid. This classification includes either a single or multiple DER systems connecting multiple buildings, but controlled by one meter at the point of common coupling.2 This microgrid class is connected to and can island from the distribution grid.

Level 3 or multiple customers / advanced microgrid; also referred to as the full feeder microgrid. This is a single or multiple DER system that serves several different buildings/customers that are not on the same meter or on the same site as the DER. An advanced microgrid has one [PCC]. The individual buildings/customers may be independently connected to the larger distribution grid and through the microgrid PCC.”

[Source: (New Jersey BPU, n.d.) cited in Jones (NASEO), Kelsey, Will McCurry (NARUC), and Kiera Zitelman (NARUC). ‘State Microgrid Policy, Programmatic, and Regulatory Framework: NASEO-NARUC Microgrids State Working Group’. National Association of State Energy Officials (NASEO) and the National Association of Regulatory Utility Commissioners (NARUC), August 2023.]

“The microgrid concept should provide a broad range of economic, technical, and environmental benefits to different stakeholders according to the use of configuration and operation schemes [3]. From the power system operator’s viewpoint, the microgrids can be considered as an aggregation concept of the coordinated control (both supply and demand-side) based on the connected, flexible distributed energy resources (DERs). From the end user’s point of view, microgrids should decrease the costs of energy, increase power quality and reliability, and offer energy services, for example.” [Source: Sirviö, K., Kauhaniemi, K., Ali Memon, A., Laaksonen, H., Kumpulainen, L., 2020. Functional Analysis of the Microgrid Concept Applied to Case Studies of the Sundom Smart Grid. Energies 13, 4223. https://doi.org/10.3390/en13164223 ]

Microgrids are classified into isolated microgrids and non-isolated microgrids. Isolated microgrids have no electrical connection to a wider electric power system. Non-isolated microgrids can act as controllable units to the electric power system and can operate in the following two modes: • grid-connected mode; • island mode. [Source: IEC. Microgrids—Part 1: Guidelines for Microgrid Projects Planning and Specification; IEC/TS 62898-1; IEC: Geneva, Switzerland, 2017; pp. 1–33.]

“Microgrids are often identified according to different kinds of communities, such as energy communities that could facilitate the power grid energy management. Participation in a community must be open to all potential local members, and it must be voluntary to join as well as leave the community [12]. For example, in energy communities, the owners of distributed energy resources (DER) participate in the energy generation that is sold to the local energy utilities, and the profits are divided among the participants. The generated electricity could also be consumed by participating prosumers, providing a valuable economic benefit of local energy generation. The Renewable Energy Directive (EU) 2018/2001 insists that local communities are organized in the vicinity of renewable energy projects they own and develop, while the Electricity Market Directive (EU) 2019/944 does not engage citizen energy communities in the same geographical location between generation and consumption [12]. The energy communities can be those such as homogenous energy communities, mixed energy communities, or self-sufficient communities. Energy communities can be composed of a part of a microgrid, a microgrid, or a subset set or a superset of microgrids that have the objective of the energy function for operation. In other words, microgrids are not equivalent to energy communities, but they can form the technical basis of microgrids.” [Source: Sirviö, K., Kauhaniemi, K., Ali Memon, A., Laaksonen, H., Kumpulainen, L., 2020. Functional Analysis of the Microgrid Concept Applied to Case Studies of the Sundom Smart Grid. Energies 13, 4223. https://doi.org/10.3390/en13164223 ]

[Source: Sirviö, K., Kauhaniemi, K., Ali Memon, A., Laaksonen, H., Kumpulainen, L., 2020. Functional Analysis of the Microgrid Concept Applied to Case Studies of the Sundom Smart Grid. Energies 13, 4223. https://doi.org/10.3390/en13164223 ]

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